The present invention relates to bicycle brakes, of the type comprising a front lever and an internal lever, set behind the front lever, both levers (callipers) being able to oscillate and each including an articulation portion from which there extend an arm for supporting a brake shoe and an actuating arm, said levers being arranged in such a way as to cross one another, and each lever being articulated in its articulation portion on a supporting pivot. In the present description and in the claims that follow, the term xe2x80x9cfrontxe2x80x9d is used with reference to the direction of advance of the bicycle.
The invention applies both to brakes of the most conventional type in which said levers are articulated on a single common pivot designed to be secured to the frame of a bicycle and to brakes of the type in which said internal lever is mounted articulated on a first pivot designed to be secured to the frame of a bicycle, and said front lever is mounted articulated by means of a second pivot on an auxiliary supporting body rigidly connected to the first pivot (see, for example, the U.S. Pat. No. 5,425,434 of the present applicant).
According to the prior art, the supporting pivot designed to be fixed to the frame of the bicycle consists of a screw, secured to the frame by means of a nut, which traverses a through hole made in each of the two levers, in the case of a brake with single pivot, or only in the internal lever in the case of a brake with dual pivot, and which has a front end head resting against the front surface of the front lever (in the case of a single-pivot brake) or of the internal lever (in the case of a dual-pivot brake). It follows that the head of the threaded pivot is visible on the front part of the corresponding lever.
In order to hide the aforesaid head of the pivot from sight, the subject of the present invention is a brake of the type referred to at the beginning of the present description, characterized in that one of the brake levers has a blind hole that opens out on to a rear surface thereof, in which an end portion of said supporting pivot is received, said end portion of said supporting pivot being withheld axially, though free to rotate, in said blind hole.
In the preferred embodiment of the invention, the aforesaid end portion of the pivot takes the form of a widened head and is axially withheld against the bottom of the blind hole by a bushing surrounding the pivot, said bushing being screwed inside a threaded portion of said blind hole.
In the case of a single-pivot brake, the blind hole is made in the front lever and the pivot is inserted through a through hole of the internal lever. The head of the pivot is withheld axially within the blind hole of the front lever by means of the aforesaid screwed bushing. Between the rear wall of the bushing and the adjacent surface of the internal lever is preferably set an axial bearing, either a friction bearing or a rolling bearing.
In the case of a dual-pivot brake, the articulation of the internal lever to the pivot fixed to the frame may be obtained in a traditional way, i.e., by providing the pivot with a head resting on the front surface of the internal lever, in that this surface is in any case hidden by the front lever. However, even in this kind of brake, the arrangement of the invention can be adopted to provide the articulation of the front lever on the aforesaid second pivot. In this case, the second pivot is secured rigidly to the auxiliary supporting body and has a head received in a blind hole made in the rear wall of the front lever, the head being axially withheld inside said blind hole by means of a bushing screwed inside it.
Thanks to the characteristics referred to above, articulation of the brake levers is obtained with an arrangement different from those of the known art, which makes it possible to hide the head of the pivot out of sight.